Panel: Will Morganza protect wetlands?

Nikki BuskeyStaff Writer

Wednesday

Oct 22, 2008 at 3:00 PM

HOUMA — Members of a panel reviewing Terrebonne’s proposed flood-protection project grilled U.S. Army Corps officials Tuesday about how the massive levee system will effect collapsing local wetlands.The answer, they were told, is that the plan is to protect existing wetlands inside the proposed system. There’s no plan to replenish wetlands via Morganza-to-the-Gulf.The Technical Review Panel, a group of scientists, engineers and others appointed by the state to examine the Morganza hurricane-protection system, held its final meeting Tuesday in Houma to review the environmental aspects of the project. Morganza is a system of levees, floodgates and a lock on the Houma Navigation Canal intended to protect Terrebonne and parts of Lafourche parish from up to a Category 3 hurricane. The state tasked a panel of experts with reviewing the project, snarled in bureaucracy for years, to determine whether it will indeed provide the flood protection promised and avoid harming Terrebonne’s sensitive wetlands. The panel had been scheduled to meet in September and prepare a report for release this month, but hurricanes Gustav and Ike delayed that time line. The final report is now scheduled for release in December.On Tuesday, the panel asked corps representatives if Morganza is designed to help address land loss in Terrebonne, long pinpointed as having the worst erosion in the state. “We’ve got to see that we’re minimizing the conflict between restoration and protection,” said Technical Panel Chairman Robert Twilley, a coastal scientist with Louisiana State University. Both are equally important to Terrebonne’s future, he added.Told that Morganza is not designed to help replenish wetlands but does aim to retain what currently exists, the panel expressed frustration.Corps biologists detailed the studies and computer modeling they’ve done to determine how Terrebonne’s complex mixture of salt, brackish and freshwater marsh could react to being walled-off from the Gulf of Mexico.The corps has proposed placing 13 so-called environmental structures throughout the levee, small gates placed strategically through the system that would remain open to allow water to pass through the 64-mile system, except during storms.But corps officials also told the panel that they haven’t decided exactly where the structures will be built, how big they will be or how many they will need to install to maintain wetlands health in Terrebonne.They’re in the process of building a complex computer model detailing water flow and salinity from Vermillion Parish to the Barataria Basin that, corps officials said. Work will continue on that model through next year.The results will determine how the structures will work and where they will be built.Nathan Dayan, a fisheries biologist with the corps, explained that the structures have to be placed in the levee to allow fish, shrimp, crab and other species to continue thriving in marshes inside and outside the levee system.They also prevent the water levels from rising inside the system and drowning the marsh that already exists.“We picked spots for the structures where we assumed there’d be ponding,” Dayan said. “That kills marsh.”Panel members were not satisfied with the lack of information about how the corps planned to manage local wetlands and asked aggressive questions as the meeting neared its end.“If this is about the wetlands behind the levee and what’s going to happen to them — and I think it is for a lot of people — we need to be vigilant,” Twilley said.Coastal scientists on the panel were also skeptical of assumptions that simply walling off wetlands from saltwater intrusion is the correct solution for Terrebonne, as frequently suggested by local levee advocates.“The wetlands did well on their own for 4,000 years. There’s clearly something fundamentally wrong with this system, and whatever this project does, it needs to help remedy that,” Twilley said.He added that he doesn’t believe it’s necessary to wait for results from time-consuming computer modeling, saying that assumptions about how the levee will interact with the environment must be challenged.Denise Reed, a professor at the University of New Orleans and a Montegut resident, insisted that the best science should be used to determine how wetlands will react to the system. “Some parts of the system have lost a lot already, and we have to understand that simply making a system fresh won’t bring it back,” Reed said.The questions will be discussed and addressed in the panel’s final report, Twilley said.All information and materials presented at the Morganza Technical Review Committee meetings will be made available on the state Coastal Protection and Restoration Authority’s Web site, www.lacpra.org.

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